I think you're right about it being good for first drafts. I find AI-written text, even the best of it, still has that "uncanny valley" effect. I can usually spot when it's been machine-written. It's somehow cold, stilted, and while grammatically correct somehow lacks pace, as if each sentence or paragraph was constructed without reference to their place in the overall flow of the story.
Where it is succeeding is in generating spam that gets past most boolean filters - I'm seeing a huge spike in the damn stuff. Where it will totally fail, I think, is in creating documentation for software, business processes, technical manuals and the like, where precision, clarity, structure and 100% accuracy (usually involving brand new products) are all essential components.
Yeah, anything like that which requires a human touch will never be outsourced to machines. At most it'll provide a first-pass that folks can then fix.